Infusão contínua com cetamina e xilazina associadas ou não ao éter gliceril guaiacolato em coelhos

Abstract

Total Intravenous Anesthesia (TIVA) is a very useful anesthetic technique in veterinary anesthetic routine. One of the anesthetic associations more used to TIVA is the Ketamine, Xylazine and GGE (Glyceryl Guaiacolate Ether), especially suitable for horses. The present study aimed to test the anesthetic protocol Ketamine and Xylazine associated or not to GGE in rabbits. It was evaluated the changes in heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean (MAP), respiratory rate (f), carbon dioxide tension at the end of exhalation (EtCO₂), rectal temperature (RT), blood concentrations of lactate and glucose and electrical stimulation reflection in rabbits submitted to Total intravenous anesthesia with two experimental protocols. Ten animals were submitted to two anesthetic procedures, with a month between them and randomly. In both groups, anesthesia was induced with Ketamine 20mg/kg associated with Xylazine at a dose of 1 mg/kg intravenously. Right after the induction, was started the continuous infusion of a solution containing 10mg/ml Ketamine, 0.3mg/ml Xylazine and 50mg/ml GGE at group called CXE Group and 10mg/mL Ketamine and 0.3 mg/ml Xylazine at group named Group CX, in the rate of 8ml/kg/hr administered by infusion pump. The parameters were measured in 10-minute intervals for 90 minutes (T10, T20 ... T90) after the start of infusion. Blood samples were taken before anesthesia induction, at T30, T60 and T90, for glucose and lactate serum levels. The SBP, DBP, and MAP were lower at all times in relation to baseline values in both groups. In GCXE the values were significantly lower than in GCX from T20 until the end of the infusion. The f was lower in T90 on GCXE. EtCO2 values were lower in GCXE at T50 and T60. RT decreased in both groups, with significant differences from T30 until the end comparing with baseline. The lactate serum concentration was significantly lower compared to baseline in the T30 at GCXE and T60 and T90 in both groups. At GCX, blood glucose was significantly higher than baseline in T90. The response to the nociceptive electrical stimulation did not differ between groups. 10 minutes after the start of the infusion (T10) 70% of the animals of the GCX showed positive response to nociceptive stimuli as well as 60% of GCXE the animals responded to the stimulus. In the 20 and 30-minute infusion (T20 and T30) only 10% of animals at GCX did not respond to noxious stimuli while 30% of animals at GCXE did not respond to noxious stimuli. From the 30-minute infusion 100% at GCX animals responded to nociceptive stimuli at all times until the 90-minute infusion (T90). In GCXE, 30% of the animals remained unresponsive to noxious stimuli and in the end VII

of ratings (T90) 80% of the animals had responded to nociceptive stimulus. The anesthetic protocol using Ketamine and Xylazine associated or not to EGG continuous infusion, at the doses used, was not enough to abolish effectively the response to nociceptive stimuli and caused severe hypotension, and is not therefore suitable for use in anesthetic routine of rabbits.